The Mercury dimes of 1916-1945 are often referred to as the misnamed U.S. coins. Liberty`s winged cap, intended to symbolize freedom of thought, was similar enough to that worn by the male god Mercury (messenger to the Roman gods), that the public assumed the obverse portrait was a depiction of Mercury. The Red Book Guide to U.S. Coins lists the series as Winged Liberty Head or "Mercury" dimes, the quotation marks indicating the misperception of the design.